Machine for cutting toric-lens grinders.



C. F. WALL e P. HARKERl MACHINE FOR CUTTING TOEIC LENS GRINDERS.

APPLICATION FILED AUG. 22, 1907 1,033,640. Patented July 23, 1912.

4 SHEETS-SHEET 2.

C. F. WALL & P. HARKER. MACHINE POR CUTTING Tomo LENS GRINDERS. APPLICATION FILED AUG. 22, 1907.

4 SHEETS-SHEET 3.

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C. P. WALL 6L F. HARKER. MACHINE FOR CUTTING TOEIC LENS GRINDERS. APPLICATION FILED AUG. 2z, 1907.

1,033,640. Patented July 23, 1912.

SHEETFSHEET 4.

UNlTED STATES PATENT QFFICE.

MACHINE FOR CUTTING TORIC-LENS GRINDERS.

Specification of Letters atent.

Patented July 23,1912.

Application filed August 22, 1903. Serial No. 389,731.

To all whom t may concern.'

Be it known that we, CHARLES F. Wim. and FREDERICK HARKER, citizens ot the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented Certain new and useful Improvements in Machines tor Cutting ToricLens Grinders; and We do hereby declare the following to be a full, elear, and exact description of the invention, sueh Will enable'others vdrilled in the art to which itl appertains to make and use the same.

This invention relates to improvementsj in machines for cuttingsr Toric lens grinders.

ln the optical art, and more particularly in the produetioii oit' lenses employed in eye-glasses and spectacles. certain eontlitions require the use of Toric lenses. lens of this character has curves of difterent radii, that is, the axes of the lenSeS are of different radii, and to produce auch a lens it is necessary to employ a grinderl the working face of which has eurvee ol' litterent radii. In the ordinary production of sut-h tools or grinders, however, much e.\' pense is involved hy reaaon of the tedious and laborious inethoos employed, and these methods are also exceedingly slow heeause ot the extreme Care that must he exerdrsed to preserve the proper curvature.

The present invention, therefore, haa for it; ohieet to provide a' maehine hy the uSe ot n'liieh 'lorit lens grinders may not only' le.: aeenrately gnouueed, but produced with rapidityy as ivell. without the eixereiee of any high degree o'l` Skill.

"lhtinvention also aim to provide u maA rhintot' the eharaeter mentioned ltiavinjjr prt-widen for Quirk and steeuratt adjustment ol' the parte'. and also ineluding #imple and eltirient means hy which the @aine may automatimilly eut the grintlew to the required rurvature and hy which the feed may he automatically stopped when the limit. of the Cutting operation has been reafhed.

With these general objects-in view, and others that will appear aa the nature ot the improvements is better understood, the ineonstrurtion, combination and arrangement of parts hereinafter fully described, illnsi trated in the accompanying drawings, and

'While the l'ora'i of the invention herein shown and derilied is hat ontv adaptation thereof, it` iS manifest that the in vention ie susceptible ot changea in the form, proportions, and minor detallay ol eonatruetion, and the right. aeeordinpgly reserved to modify or var); the intention :is vtallal Within the spirit and, Scope thereof.

ln the drawings. Figure l is a front elevation ot a machine embodying the hereintleserited improvements. Fie'. 2 is an end. elevation thereof. Fig. a top plan view ot' the mat-hint. Figs. i' and 5 are detail fragmentary vieu'S illustrating` the shifting liar and the actuating rod therefor in (litterent pofsitions. Fig. G is a tranaverse Seetlonal vien' on the line tr-t, Fig. 5. Fig. T ie ateo a detail fragmentary view ot thel shitting har and the actuatingy rod. the guide el1 the latter beingV reversed. Figs. S. il. and l0 are detail fit-uu et the eutter and its holder. Fig. 11 is a traneverse are tional view of the chuck tor holding` the tool blank.` Fig. l2 is a longitudil'ial sectional View thereof. Fig. 13 i@ a side elevation ol the tlutclrlever engaging hook Carried hy the Shifting' liar. and ilhntrated as engaged v'ith the eluteh lever. Fig'. ll iew a detail elevation ol' u Torn' lem grin-ler jn'oduted hy the herein deerihewl maehine.

Referring" in detail tothe uemmpaiiyinfr drawings, the numeral l designatiVH the h ot the hereiudefsrrihed machine` upon ehirh mounted a vertical column i the upper' portion of Which provide@ heariuga for a main Shaft 3 upon whirh is mounted a contpttlley l and at the upper end ol' the f'olltnin uo oterhanging arm iS proi.. the 'free end of the arm providing a hea. .tg tor a live Spindle The eolumn Q ifs at@ prtwided with a knee 7 having,y #uit ahh; trevieit-n for vertical adjustment, and aid knee provided with a platen 3 upon .vhioh a saddle 9 is mounted, Said Saddle' having adjustment longitudinally of the platen 5% through the medium ol a 'feed seran* lt?.

The Vparts thus l'ar deaerihed are what are tzonfttnonly found in i taudard forms of milling machines.. and it ia therefore unl necessary to delrrihe in further det-,til Such l parts. p

iivoti'tllj.' mounted upon the Saddle 9, aS .Qlionn by dotted lines in Fig. 3, is a Work table l1 and arranged upon Said A L, Wort toe table is a tail plate 12 having a longitudinally-extending groove 13 formed therein, and slidabl mounted inv Said groove, and adjustably lield therein through the medium .of a bolt 14, is a chuck support 15 the chuck 16 of which is slidably mounted therein and held against rotation through the medium of ascrew 17 that engages a longitudinally-extending groove 18 formed in said chuck. A feed screw 19 engages the outer end of the chuck 16, and through the medium of said feed screw it will be seen that the chuck 16 may be adjusted within the support 15, the inner end of the chuck, or that end which lies nearest the live spindle 6, receiving the tool blank 20, as shown by dotted lines in Fig. t2. Vhen the tool blank has been properly positioned and the chuck 16 properly adjusted, it is essential that it should be held in this position, and to this end a binding screw 21 operating upoii abearing plug 22, is filled in a screw-threaded head 23 that is secured upon the upper portion of the support 15, the plug 22 fitting an opening in said support, and having its inner end bearing upon the chuck 16.

For shaping the tool blank 20 to impart thereto curves of different radii, the form of the cutter lshown in Figs. 8, 9 and 10 is preferably employed. This cutter comprises a holding disk 24 provided with a central opening 25 in order to receive the live spindle 6 of the machine and be held there in the usual manner common to the attachment of milling cutters, and mounted in a radial groove 26 in said disk is a cutting blade 2T that is held in position in said `groove through the medium of a binding screw 26 carried by a yoke 29 that bridges the groove 26. It will be observed that the outer end ef the blade 27 projects sufficiently beyond the edge of the. holding disk 24 for action upon the tool blank 20 during the rotation of seid disk, and said blade attacks the tool blank once upon each revolution of the live spindle 6. j

For effecting proper feed of the work to the cutter', the work being held stationary in the chuck 16, as before described, the table 11 is caused to swing upon its pivot, and to this end the periphery of said table is provided with worm teeth 30, so that in effect the table 1l constitutes a Worm wheel, and meshing with said teeth 3() is a worm gear 31 carried by a counter-shaft 32 journaled n -in bearings 33, which bearings in turn are mounted upon the saddle 9 in rear of the work table 11. A hand wheel 34 is carried by the shaft 32 at its outer extremity, wherebv said shaft may be manually operated when it is desired to effect a quick adjustment of the work table upon its pivot, but in order that a gradualadjustment of the work table upon its pivot may be effected a sprocket wheel 35 is also mounted upon the shaft 32, over which sprocket Vwheel a sprocket chain 36 is adapted to work, said sprocket chain being also connected to and working over a sprocket pinion 37 mounted upon a counter-shaft 3S arranged beyond the counter-shaft 32 and parallel with the latter.- The counter-shaft 38 is journaled in bearings 39 that are carried by va plate 40, and said plate is provided with a transversely extending slot 41 in which a binding bolt 42 is mounted, the purpose of the binding bolt 42 and the slot 41 being to permit adjustment of the plate 40 upon a supporting plate 43 adjustably mounted upon the saddle 9. A spur gear 44 is mounted upon the end of the shaft 38 that is opposite to the pinion 37, said gear 44 meshing With a pinion 45 that is mounted upon a countershaft 46, and said shaft 46 is journaled in bearings 47 that are carried by the plate 43. The plate 43 is adjustably held upon the saddle 9 through the medium of a clamping bolt 4S, and it will thus be seen that by the adjustability of the plate 43 the shafts 3S and 46 can be moved without disturbing the relation of the `gears 44 and 45 for tensioning the sprocket chain 36, or loosening the same. Connected to the shaft 46 through the medium of a. universal joint 49 is one end of a telescopic shaft 50, the other end of said shaft being connected through a universal joint 51 with the shaft of a lower cone pulley 52 connected to an upper cone pullev 53 through the medium of a belt 54. Standard reversing mechanism 55 is interposed between the universal joint 51 and the shaft of the lower pulley 52 for effecting a reversal of the movement vof the shaft 50, and as the elements 49, 50, 51, 52, 53, 54

and 55 are of the usual construction found in milling machines it is not deemed necessary to further describe the same, nor to illustrate them other than conventionally. Sufliee it to say that these elements are relied upon for effecting the, operation of the other elements constituting the feed mechanism for moving the work table 11 upon its pivot, and. thereby causing movement of the tool blank across the eut-ter in substantially a horizontal plane, and reversal thereof.

As before premised, the present invention contemplates a machine wherein provision is made for stopping movement o the tool blank in relation to the cutter when the limit of the cutting operation has been reached. To the accomplishment of this end a plurality of depending hanger arms 56 are attached to thc upper port-ion of the column 2, the lower ends of said arms terminating in horizontally disposed sleeves 57, and in said sleeves is slidably mounted a shifting bar 58. lt is preferable that the bar 58 shall be square in. cross section, and the sleeves 57 therefore conform to such con- '4 pair ot' pir einsam@ figuration in einer to prevent rotation of the shifting bur 5B. The shifting bar is of suflicient length for therend thereof thdt, lies in proximity to the enne pulley b3 to prejef't suine dietnnee beyond the. adjacent sleeve 5T, und mounted upon said end is un engaging hoek 59 :uljiniiably secured to the bnr through the medium of n clamping screw 60. Thus it will he seen that the honk 59 may he nfljnete'il llene; the shifting; 'nur 35S. und said howl: designa! in engnge n noleh 61 formell in the enl'l nlE n eluteh lever 62. This elntrh lever ie eiinilnrlotlmt onnim'only fonnll in milling nnieiiinea for eonneeiing nini lism'mrmeting he feed n ith the main Shaft ot' Snell nnn'hines, und in the prer- ,ent rase nlufh rluteh mech-(miem Pennei'fts :intl

disronneets the 'upper none Bil with the nniin shall l ol the'l'nln'l'iine. ll'henthe hook 59 is engaged with the elnleh lever l2 the hitler is held Yin elevated position against the nur ion nl.' n -Qpring GEB, that if: connected to the ('luth lever (32 through the niellinin of a hookl., Said spring being in tnrn mnneeteljl to the body Erf-the. inziehine, nr annifeontigir one nifl thereof, ihr-:nigh the niefliunz nl" n roll 65. Wren the Qlutafli lever 62 in held in the elevated poiition referred to the feed mediums-m is eonneetell lo the malin shari ofthe machine, und long' ne this vennen tion 'is maintained the feed ol" the- Wwrli aereas the cutter in the manner prerinnely (lesrrihed, is e'eeted. When, however1 the hook disengaged from l[he nlntzeli lever G2 the spring 6? merli its tension to pull l the olutch lever 62 in :L downward direetinn, and the 'feed meehanism ist thereiny (limonneetetl fron: the main shaft :intl the feell of the work irninerlinlelf.' ceases To ell'eet this diwngngenient of the honk 59 nn hetnet ing rofl (3G is ennlilnyed, onneled tu ene end of Savill stemming rnd is an open gnirle llehnpe and ehifting r EN.

r[he guide HT is iiiwnlly ecimedeil` nl" CS. to the eclnning hui' nth the pli nml point, being nearer one enfl et' the guide (T than the, other @nil ille-rent, :intl in or'ler flint the gnifle (3T nml." r 'e the Shifting hair .En lo slide in the sie( 5'?, unil lherehi franse (Alle hook lil A out ni' the untel! lli. n l rernnvelily @e el in n rief; "it npeningz 'TV1 formez" in the l vy spueell inlerw` 1. ille gnirle reeli'in nl' ile ixn'nenient nl (nulmeting with ne nr the mini GS), and thereby enabling the gnnle 37. nncler the movement nf the netnfilving rod (313, lo more the shifting hm' for the purpose Stntell. lt is manifest tlmlh v adjusting the punition nl the pins (il) to var v the (listlinees tlierehetween the gnifle 6T will have more 0r plu); upon the shifting hnr 5S heter@ the nig A reuse le one! 6T. which guide il nlz Ruljmrtiinlial inverted g l@lillnhly nnnintell 11p-nn the,

the movement of the actuating rod 66, and the purpose of this will preeently appear.

To effect movement of the actuating roll (in the end thereof opposite to that whereon the guide 6T is pivntell is e'liflahlyinountell in n guide sleeve 7i, which guide sleeve in turn is pivolnlly (funnel-ted to the upper portion of 1h@ chuck support 15, the aetuniing rod having 'free moieinent in rnifl guide Sleeve Tl. but lo limi! the ni-:ireinenl thereof in yrelation to the guitle sleeve T1 zin rulliniA nhle stop is mounted in euch side of the `leere Trl. Thus it will he eeen that the Lieglee yof nnnlenienl et the leere between the Stop T2 earn he seriell hy adjusting the space between will eww, .sind ermseqnenlly .the sleeae T1 will have n (fernin degree ot play upon the netnaling roll 16, i :i nnmner similar to the piny of the guide (ST upon the Llifting har 5e. before ronlnrtingr with either of lhe ,slope Til. when hor-ever. -zin^l1 eontart takerl iiue the ziflnntiig rml 5G iin gills tu move in the direction of infiniment of the sleeve 7L sind thi` in turn ixnpnrls tl the guide eleew (ET n similar movement, so that when ihn leiter wines in eontnet with one .of the pinel (Ell the shitting lmr ,US veghh4 also to more finzi ennlinnes no lo lo nnlil the engaging hfmli 59 is relelrnztl frnni the rin-teh lever l i. This i'lisengffigeinent ennse; the spring (lill ne previously (lenerihetl, lo pull the Clutch lever G2 (lownwn wily, ninl the feed of the Work is tliereliy etoppell lit' in evident` that the splice hetneen the stops 'l'. :intl lilnlr'iee lauw-een the pine, U9. will he fleierniinel'i hy lhe unionnt of movement neeessnny for swinging the ture nf the tml lilanlt zieren` the eviter, und when the tml ltlnnl: in 11n-Wed enlirely arrow the ruiter; intl ihe limit nl the Hitting opel-:nimm is thereby renfhvll. ille feed meclniniun will ie unil consequently fnrlher movement, in ellher flireetilln nl' (he work tnlllffg s1/ill eerie.

i 2li:- lngierltinn of the liereinflwvrillell rell in the rhuf'lt le, fz rlepressinn fill in the .elmnlt ol' the tool l unl; rereiring n hinrlinf,r zei-ew lll ":irrlml the rhin if. 'l his engngenienl ut' the Qrrlr" 144i nizh the lllol lllnnl; holllw the lz1tn position in the mine horiz/mitnl pinne :nl

l l l l i i einwnlure that latter begins tn more under the mtinenee nt' i the center of the live spindle 6. So lhnt the crest of anch Curve lo he rut will intersect the Crest of the ether Curve :it the Center ot' he tool blank. Vl'lnving' llanay :nljnsnll the mol hlnnli. mail fleerininwl the desired n) ll;- iniparted in the blank in u direction nernsq the time thereof,

or in a horizontal plane, measurement is taken from the center or pivot of the work holder 11 through the medium, preferably, of a steel square. 'hen the desired radius is thus measured, the. face ot the tool blank is moved up to the square so that the latter will contact with the edges of the face of the blank, whereupon the screw 21 is tightened to clamp the chuck 16 in the support 15, and the bolt 14 bei g also tightened to hold the support 15 in fixed position upon the tail-piece 12, it is evident that the tool blank is in position to receive the required curvature for the long axis of the grinder. For very tine adjustment of the tool blank relatively to the center of the table 11 the feed-screw 19 is employed. The curvature of the Ishort axis of the grinder is easily determined by merely set-ting the cutting point of the cutter 27 a distance from the center of the live spindle 6 corresponding to the radius previously determined upon, after which the cutter fastened against movement by the screw 28. Various diameters of the holding disk 2t obviously can be employed. For feeding the tool blank to or from the cutting blade 27 without changing the radius of either the long or short axis the feed screw 10 is operated. The position of the chuck support 15 in relation to the pivot of the work table 11 thereby remains fixed.

With the tool blank positioned as described, the machine is set in operation, power being applied to the cone pulley 4, and with the clutch lever 32 in its raised position, and held therein by the engagement of thehook 5t) therewith, it will be seen that movement is transmitted through'the pulley 53 and the intermediate connections to the countcrshaft 32. As the gears 44 and 45 and the sprocket wheels 35 and 37 are properly proportioned, only a slow movement is given to the countershaft 32. This movement through the worm gear 3l to the teeth 30 causes the work table 11 to move slowly about its pivot, thereby sv. inging the tool blank that is carried by the chuck tti across the cutter carried by the live spindle tt, When the limit of the cutting operation has been reached, the hook 59 becomes disengaged from the clutch lever (i2, and the feed of the work immediatelyl ceases, as previousl)7 described. Operation ofthe reversing mechanism 55 causes' a reversal ofmovement of the feed table 1l, and the tool blank returns across the cutter to be again operated on thereby, but in order to permit this reversal it is, of course, necessary to raise the clutch lever (i2 so that the feed mechanism may be again connected to and operated Afrom the shaft 3, and to enable the clutch lever 62 to be engaged by the hook and held thereby in its raised position 1t 1s first necessary to reverse the position of the -the action of a single cutter'.

guide 67 otherwise, the shifting bar 58 having been moved to its limit in one direction, reverse movement thereof to bring the hook 59 into engagement with the clutch lever 62 cannot be imparted thereto by reas n of engagement oit' the guide 67 with one of the pins Gt). This is the purpose of providing the pivotal connection of the guide 67 With the actuating rod 66 at a point near one end of said guide, and by referring to Figs. 4,

and 7 the reverse positions of the guide 67, in Vthe two directions of movement, are clearly shown, the arrows indicating the directions of movement. It will be understood -th at before reversing the feed the tool blank is moved slightly toward the cutter through the manipulation of the feed screw 10, and as the cutting operation proceeds on the return movement of the tool blank a reverse movement of the actuating rod 66 takes place, which, in turn, causes a reverse movement of the shifting bar 58. When the limit of the cutting operation in this reverse direction is reached, the hook 59 is again disengaged from the clutch lever 62, but this time by a reverse lateral movement of said hook and, consequently, the feed mechanism again comes to rest. This operation is repeated to the necessary extent for imparting to the face of the tool blank the required cut to produce the desired curves, and when this has been completed the tool blank is removed, and a new one inserted in the chuck, a like operation being re eated from time to time on the respective ilanks until the required curvature has been imparted to each.

From the foregoing it will be seen that the present machine is capable of cutting a Toric lens grinder and simultaneously'im- 105 parting thereto curves of different radii by After the blank has been placed in the chuck the machine will auton'iatically operate in cutting the blanks, and the only attention that is 110 required is merely to etleet a reversal of the l'eed mechanism when the limit of the cutting y,poration in cach direction of movemeuty ot the work has been reachctjl.y No hie'h degree of skill is therefore necessary, 115 and a single attendant may readily operate a plurality of machines thereby producing Toric lens grinders in an expeditious manner, and at the same time producing them with the highest degree of accuracy with respect to the curvature thereof.

Having thus described the invention, what is claimed as new, and desired to be secured by Letters Patent, is:

1. In a machine of the class descr1bed, a 125 cutting element mounted for movementin an arcuate path, a work support arranged to move the work in an arcuate p ath across the plane of movement of the Cutting ele. nient, means for driving the Operative elements, a shifting bar operatively related to said driving means, and an actuating rod interposed between said shifting bar and `the Work support and slidably connected to each for operating the shifting bar to stop the movement of the driving means when the limit Yof the cutting operation has been reached.

2. In a machine of the class described, a cutting element mounted for movement in an arcuate path, a workl support arranged' to move the work in an arcuate path across the plane of movement of the cutting-element, means for'driving the cutting element and said work support, gearing mterposed between the driving means for the. cutting element and the means for driving thework support, a clutch included in said gearing, a shifting bar having a detachable connection with said clutch, means interposed between s-aid shifting bar and s'aid work sup',-

port and actuated by the latter to cause theA shifting bar to become disengaged from said clutch when the limit of the cutting operation has been reached, and means to actuate said clutch when said disengagement tgkes place to stop movement of the work suport. w p 3. In a machine of the class described, a cutting elenienumounted for movement in an arcuate path, a work support arranged to move thev work 1n an arcuate path across `the plane of movement of the cutting element,

means for driving the cutting elen'ient and said work support, gearing interposed between the driving means for the cutting element and the means for driving the work support, a clutch included in said gearing, a

shift-ing bar having a detachable connection with said clutch, an actuating rod inte-rposed between said shifting bar and said work support and actuated by the Work support to cause the shifting bar to become dis engaged from said clutch when the limit of the cutting operation has been reached, adjustable stops associated with said shifting bar'- to limit the movement of the actuating rod thereon, and adjustable stops for limiting movement of the work suppoit in rela- `tion to said actuating bar,

4. In a machine of the class described, a cutting element mounted. Jfor movement in an arcuate path a work support arranged to more the vork in arcuate path across the plane of: movement of the cutting element, means for driving the cutting element and said work support, gearing interposed between the driving means for the cutting element and the means Vfor driving the work support, a ciutch included in. said gearing, a shifting bar having a detachable connection with said clinch, an actuating rod posed between said shifting bar n work support and actuated by the vfoiit support to cause the shifting bar to become disengaged .from said/clutch when the limit of the cutting operation has been reached, adjustable stops associated with said shifting harto limit the movementfof the actuating -rod thereon, adjustable stops for limiting movement of the work support in relationto said actuating bar, and means tonact-uate said clutch when said disengagement :'takesf iment andthe means for driving the work support, a clutch included in said gearing, a shiftingA bar having a detachable eonnectlon with said clutch, adjustable stops carried by .said shifting bar, an actuating rod interposed between said shifting bar and said work support and actuated by the work support to. cause theshifting bar to become disengaged from said clutch when'the limit of the cutting operation has been reached, a guide carried by said actuating rod and slidably mounted upon said shifting bar between the adjustable stops thereof, a pivoted guide carried by said work support and in which said actuating rod is slidably mounted, and adjustable stops mounted upon said actuating rod at the sides of. said pivoted guide for 'limiting movement of said guide upon said actuating rod.

6. In a machine vof the class described, a cutting element mounted for movement in an arcuate path, a work holder, a pivoted support upon which said work'holder is mounted, a ,countershaft geared to said piv oted support for actuating the latter and thereby to move the work holder in an arcuate path across the plane of movement of the cutting element, a second counter-shaft adjustably mounted in relation to the rstf. named counter-shaft and geared thereto for actuating the latter, and means'for driving the cutting element and the second countershaft,

7. In a machine of the clade described, a cutting element mounted for movement in an arcuate path, a work holder, a pivoted support upon which said work .holder is mounted, a cennteushaft geared to said pivl oted r eport for actuating the latter and thier i nove the work holder in an arcuate :ross the plane of movement 0f the cu g eiement, means for operating the ing element, gearing interposed between countershaft and the means for operthe cutting element, a clutch included 1n said gearing, and means controlledby the movement of the work holder for actuating said clutch to disconnect said gearing Vfrom the cutter-operating means when the limit of the cutting operation has been reached.

8. In a machine of the class'described, a cutting element mounted for movement in an arcuate path, a work holder, a pivoted Support upon which" said Iwork holder is mounted, gear teeth carried by said pivoted support, a counter-shaQjournaled in proximity to said pivoted support,- a worm gear carried by said counter-shaft and meshing Wit-h thev teeth of said pivoted sup ort, whereby to actuate the lattenand thereg'y to move the Work holder in an arcuate/path across the plane of movement efl thecutting element, means for operating the cutting element, a second counter-Shaft adjustablylr mounted in relation to the/irst-named-coun-j ter-shaft, gearing interposed between said 'second counter shaft and the rst named counter shaft, gearing interposed between the second counter-shaft and the means for operating the cutting element, a clutch included in said gearing and adapted to disconnect the latter from the means for operating the cutting element, and means interposed between said clutch and the Work holder and controlled by the movement of the latter for effecting operation of Said clutch when the limit of the cutting operation' has been reached.

ntestimny Whereofwe alix our signatures, in the presence of two witnesses. CHARLESE. WALL. FREDERIEK HARKER. VVitness'es f lfHA/RnrBoWiisy Y WM. S. BOWEN,` J/x' 

